sigwait(3) [osf1 man page]
sigwait(3) Library Functions Manual sigwait(3) NAME
sigwait, sigwaitinfo, sigtimedwait - Suspends a calling thread until a signal arrives. LIBRARY
Threads Library (libpthread.so): sigwait() Realtime Library (librt.a, librt.so): sigwaitinfo(), sigtimedwait() SYNOPSIS
#include <signal.h> int sigwait( const sigset_t *set, int *signal); int sigwaitinfo( const sigset_t *set, siginfo_t *info); int sigtimedwait( const sigset_t *set, siginfo_t *info, const struct timespec *timeout); PARAMETERS
Specifies the set of signals to wait for. Returns the signal number of the selected signal. (See the DESCRIPTION section for information about the selected signal.) Specifies a pointer to a siginfo structure that is receiving data describing the signal, including any appli- cation-defined data specified when the signal was posted. Specifies a timeout for the wait. If timeout is null, the argument is ignored. DESCRIPTION
The sigwait functions suspend the calling thread until at least one of the signals in the set parameter is in the caller's set of pending signals. When this happens, one of those signals is automatically selected and removed from the set of pending signals. The signal number identifying that signal is then returned. For the sigwait() function, the signal number is stored in the signal argument. For the sigwaitinfo() and sigtimedwait() functions, if the info argument is specified, the selected signal number is stored in the si_signo member of siginfo structure, and the cause of the signal is stored in the si_code member. If any value is queued to the selected signal, the first queued value is dequeued and stored in the si_value member of info. If no value is queued, the content of the si_value member is undefined. For sigtimedwait(), if the timeout parameter is specified, the function waits for the specified time interval. If the timespec structure specified contains a timeout value of zero (0), and if none of the signals specified by set are pending, then sigtimedwait() returns imme- diately with an error. The effect is unspecified if any signals in the set parameter are not blocked when the sigwait functions are called. The set parameter is created using the set manipulation functions sigemptyset(), sigfillset(), sigaddset(), and sigdelset(). If, while the sigwait functions are waiting, a signal occurs that is eligible for delivery (that is, not blocked by the signal mask), that signal is handled asynchronously and the wait is interrupted. RETURN VALUES
Upon successful completion, the sigwait() function returns 0 (zero). The other functions return the number of the selected signal. On failure, sigwait() returns the errno value for the failure. The other functions return -1 and set errno to indicate the error. ERRORS
If the sigwait functions fail, errno is set to one of the following values: [EINVAL] The value of the set parameter contains an invalid or unsupported signal number. [EINVAL] The timeout argument specified a tv_nsec value that is less than 0 or greater than or equal to 1,000,000,000. [EINTR] The wait was interrupted by an unblocked, caught signal. [EAGAIN] No signal specified by set was delivered within the specified timeout period. RELATED INFORMATION
Headers: siginfo(5) Functions: sigaction(2), sigpending(2), sigsuspend(2) Routines: sigaddset(3), sigdelset(3), sigemptyset(3), sigfillset(3) delim off sigwait(3)
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sigwaitinfo(3RT) Realtime Library Functions sigwaitinfo(3RT) NAME
sigwaitinfo, sigtimedwait - wait for queued signals SYNOPSIS
cc [ flag... ] file... -lrt [ library... ] #include <signal.h> int sigwaitinfo(const sigset_t *restrict set, siginfo_t *restrict info); int sigtimedwait(const sigset_t *restrict set, siginfo_t *restrict info, const struct timespec *restrict timeout); DESCRIPTION
The sigwaitinfo() function selects the pending signal from the set specified by set. Should any of multiple pending signals in the range SIGRTMIN to SIGRTMAX be selected, it will be the lowest numbered one. The selection order between realtime and non-realtime signals, or between multiple pending non-realtime signals, is unspecified. If no signal in set is pending at the time of the call, the calling thread is suspended until one or more signals in set become pending or until it is interrupted by an unblocked, caught signal. The sigwaitinfo() function behaves the same as the sigwait(2) function if the info argument is NULL. If the info argument is non-NULL, the sigwaitinfo() function behaves the same as sigwait(2), except that the selected signal number is stored in the si_signo member, and the cause of the signal is stored in the si_code member. If any value is queued to the selected signal, the first such queued value is dequeued and, if the info argument is non-NULL, the value is stored in the si_value member of info. The system resource used to queue the signal will be released and made available to queue other signals. If no value is queued, the content of the si_value member is undefined. If no further signals are queued for the selected signal, the pending indication for that signal will be reset. If the value of the si_code mem- ber is SI_NOINFO, only the si_signo member of siginfo_t is meaningful, and the value of all other members is unspecified. The sigtimedwait() function behaves the same as sigwaitinfo() except that if none of the signals specified by set are pending, sigtimed- wait() waits for the time interval specified in the timespec structure referenced by timeout. If the timespec structure pointed to by time- out is zero-valued and if none of the signals specified by set are pending, then sigtimedwait() returns immediately with an error. If time- out is the NULL pointer, the behavior is unspecified. If, while sigwaitinfo() or sigtimedwait() is waiting, a signal occurs which is eligible for delivery (that is, not blocked by the process signal mask), that signal is handled asynchronously and the wait is interrupted. RETURN VALUES
Upon successful completion (that is, one of the signals specified by set is pending or is generated) sigwaitinfo() and sigtimedwait() will return the selected signal number. Otherwise, the function returns -1 and sets errno to indicate the error. ERRORS
The sigwaitinfo() and sigtimedwait() functions will fail if: EINTR The wait was interrupted by an unblocked, caught signal. ENOSYS The sigwaitinfo() and sigtimedwait() functions are not supported. The sigtimedwait() function will also fail if: EAGAIN No signal specified by set was generated within the specified timeout period. The sigtimedwait() function may also fail if: EINVAL The timeout argument specified a tv_nsec value less than zero or greater than or equal to 1000 million. The system only checks for this error if no signal is pending in set and it is necessary to wait. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |Async-Safe | +-----------------------------+-----------------------------+ SEE ALSO
time(2), sigqueue(3RT), siginfo.h(3HEAD), signal.h(3HEAD), time.h(3HEAD), attributes(5), standards(5) SunOS 5.10 1 Nov 2003 sigwaitinfo(3RT)